Set energy range

The spectrometer can be set to give a variable energy range depending on the experimental requirements. To change the energy range:

Set the energy range using the Dispersion setting that you can access in spectrometer control region of the Microscope System palette

Use a small eV/ch setting (large dispersion) for detailed spectra around an edge or the ZLP

Use a large eV/ch setting (small dispersion) microanalysis or mapping

If the exposure is set to Auto, the exposure time will automatically adjust as the energy loss is changed. This is very useful when going from high to a low energy offset. The auto feature will predict the large increase in intensity and adjust accordingly.

For compositional analysis, only lower dispersions (big numbers) are suited. In general for compositional analysis and fast mapping, a dispersion of 1 eV/ch seems to be optimal because it gives the biggest field of view (2000 eV in the GIF Quantum® system) and the highest intensity on the CCD and EELS.

Make sure the sample is thin by acquiring a relative thickness map. If it is thick (e.g., relative thickness >1), try moving to another sample area. Increase the number of collected electrons by one (or all) of the following: